Nova-like Cataclysmic Variables in the Infrared

Novalike cataclysmic variables have persistently high mass transfer rates and prominent steady state accretion disks. We present an analysis of infrared observations of twelve novalikes obtained from the Two Micron All Sky Survey, the Spitzer Space Telescope, and the Wide-field Infrared Survey Explorer All Sky Survey. The presence of an infrared excess at >3-5 microns over the expectation of a theoretical steady state accretion disk is ubiquitous in our sample. The strength of the infrared excess is not correlated with orbital period, but shows a statistically significant correlation (but shallow trend) with system inclination that might be partially (but not completely) linked to the increasing view of the cooler outer accretion disk and disk rim at higher inclinations. We discuss the possible origin of the infrared excess in terms of emission from bremsstrahlung or circumbinary dust, with either mechanism facilitated by the mass outflows (e.g., disk wind/corona, accretion stream overflow, and so on) present in novalikes. Our comparison of the relative advantages and disadvantages of either mechanism for explaining the observations suggests that the situation is rather ambiguous, largely circumstantial, and in need of stricter observational constraints.Peer reviewe

Newcomb’s data on ancient eclipses revisited1

Relying on the Greek text related to Babylonian-Hellenic observations of lunar eclipses in Ptolemy’s 'Almagest' (Halma M., 1813) and by analysing some Arabian notes about solar and lunar eclipses - for which S. Newcomb found considerable deviations from the adopted theory - a re-analysis of his results and conclusions is herewith undertaken. The results of ancient data revision are based on Newcomb’s alternative presumption that these discrepancies are caused by one or more unknown long-term inequalities in the motion of the Moon. A quantitative analysis of ancient eclipse observations unambiguously indicates that they definitely are not to be rejected provided, of course, that they are interpreted in proper way

Étude minéralogique des phyllites de quelques minerais de fer de Serbie (Yougoslavie)

Les minerais de fer oolithiques de Serbie d'âge crétacé forment des couches et des lentilles dans des grès et des conglomérats. Tous ces minerais sont constitués par des oxydes et des hydroxydes de fer associés à des quantités notables de silicates. Ceux-ci appartiennent à deux groupes, soit des phyllites à 7 Å de type berthiérine, soit des phyllites à 14 Å qui sont des chlorites peu stables auxquelles on réserve le nom de pseudochlorites. La présente étude a permis de retrouver dans la formation ferrifère oolithique de Serbie des constituants silicatés analogues à ceux identifiés dans le bassin de Lorraine. Signalons cependant que nous avons trouvé dans le gisement de Gledić, associée à la berthiérine, une phyllite dont les caractères sont ceux d'une véritable chlorite.Protitch M. Étude minéralogique des phyllites de quelques minerais de fer de Serbie (Yougoslavie). In: Bulletin de la Société française de Minéralogie et de Cristallographie, volume 78, 10-12, 1955. pp. 528-534

CCD astrometric observations of minor planets at the Belgrade observatory during 1999 (II)

76 precise astrometric positions of six observed minor planets (two NEO among them) are calculated. The SBIG ST-8 camera attached to Askania astrograph of Belgrade Observatory was used in the observations

Precise CCD astrometric observations of minor planets and comets at the Belgrade observatory during 1997

73 precise astrometric positions of seven comets and two minor planets from MPC critical list - 1093 Freda and 4954 Eric - were obtained with the CCD equipped Askania astrograph (13.5/160) of Belgrade Astronomical Observatory. The SBIG ST-7 and ST-7 CCD cameras were used in the observations

CCD astrometric observations of comets at the Belgrade observatory during 1998 - 2000 (I)

143 precise astrometric positions of seven comets were obtained with the CCD equipped Askania astrograph (13.5/160) of Belgrade Astronomical Observatory. The SBIG ST-8(1530 × 1020 pixel array) camera was used in the observations

145CCD astrometric positions of comets and minor planets: Observed during March-September 1998 at the Belgrade observatory

In this paper we present precise astrometric positions of four comets and four minor planets from the MPC critical list. All the observations were carried out with CCD equipped Askania astrograph (13.5/160). The SBIG ST-8 camera was used. Comet 1998 M5 (Stonehouse) occulted an anonymous star on July 9 and that phenomenon was observed successfully